The documentation at https://support.displaylink.com/knowledgebase/articles/1181623-displaylink-ubuntu-driver-after-recent-x-upgrades suggests creating a configuration file in /usr/share/X11/xorg.conf.d, however configuration in this directory may be ignored in favor of user-specific config at /etc/X11/xorg.conf.d. See https://bbs.archlinux.org/viewtopic.php?id=198719 for an explanation.